Six methods of separating chemicals are filtration, chromatography, distillation, evaporation, centrifugation and using a separating funnel. Chromatography, distillation and evaporation are used to separate solutions, in which one or more chemicals are dissolved in a solvent. Filtration, centrifugation and separating funnels are used to separate mixtures of insoluble chemicals.
In filtration, a mixture is passed through a porous membrane or filter that allows only liquid and dissolved chemicals to pass through. The insoluble substances of the mixture remain on the filter. When filtration does not work, centrifugation separates mixtures of liquids and solids by spinning a vial of the mixture. The spinning forces the solids in the mixture to the bottom of the vial, allowing the liquid components to be removed.
Distillation and evaporation are similar since both methods involve vaporizing a liquid and leaving behind solids or liquids with higher boiling points. The vapor is collected and condensed in distillation while the remaining solid is collected in evaporation.
Chromatography separates colored chemicals based on relative density. When a drop of solution is placed on a vertical sheet of chromatography paper, less dense chemicals travel farther up the paper.
Separating funnels are vessels used to separate mixtures of insoluble or partially soluble liquids. When the mixture is left to sit in the funnel, the liquids to separate by density. The liquids are then removed from the funnel one at a time.